Known image compression methods are most often based on models in which both compression quality (or the distortion engendered by the compression operation) and the throughput obtained after compression are factors. The drawback of these solutions is that they control compression quality via a subordinate quantity, namely throughput, and most often only allow overall quality (of all the image) to be controlled and not local quality.
For applications that are not subject to throughput constraints, there is a need for an image compression method that allows a target quality to be obtained in each zone or block of the image independently of throughput. Such applications especially include the transmission of images from an observation satellite to a ground station. The images captured by an observation satellite correspond to images of large size for which the compression quality is a preponderant parameter, whereas the transmission channel of the downlink between the satellite and the ground is most often compatible with higher transmission throughputs than is the case in other wireless transmission applications.
Moreover, the image compression methods described in documents FR3013490 and EP1037470 are known.
The method described in document FR3013490 has the drawback of employing a complex iterative process that is difficult to reconcile with an implementation on a device of limited resources. The method described in document EP1037470 is based on modelling distortion, which depends on throughput.